Numerous misfires?

[pods8]

Not sure about that I would tend to think that it would be the cup dimensions. I sure would not rule out the possibility of a weak firing pin spring. What caliber is the rifle? Do you measure shoulder bump when you resize?

Well I just broke down all those rounds and in doing so the anvils fell out of half of the unfired primers. I also deprimed some fired WLRM primers to check those out, on those the cups were under 0.120" BUT the anvil legs were solidly proud of the cup at 0.1280". I even squeezed one in pliers (spent primer) to see if the anvil would go flush with the cup rim like on the 9.5Ms, nope. Didn't budge, a bit of deformation of the legs from the pliers took the height to 0.1240" but the anvil didn't move into the cup or loosen at all.

Are all anvils supposed to be more like the WLRM ones? There is no way the RCBS primer would push those ones into the cup, but it seems quite likely with the 9.5Ms.


Yes I measure should bump. Caliber I left off as not to spark a whole "why mag primers" (which I already answered, it was a supply issue and the loads were worked up with them in mind starting low) but to answer its 7-08. This is two rifles, not just one.

 

[Lefty7mmstw]

As long as you acct for the hotter primer in a mid sized round like the 7-08 it is of no consequence. One of my best 243 loads was a stick powder (v540) lit by a 215.... Even more than you are using.
I'd rather see people using a bit more primer. The ammo is usually better/ more uniform at low temps. when they use plenty of primer. You run into dangerous situations (hang fires and bullets stuck in the barrel are possible) in cold weather with a very mild primer for a powder charge. I've even seen hang fires in a 30-06 in cold temps. with factory ammo loaded with standard primers.

First I'd look at your case dimensions. If you have a bit of headspace and/ or you aren't whacking the primer as hard as you ought to (weak spring or too deep of a primer) it will show up differently in different brands, mostly as the primer cup thickness will differ a bit and the primer will absorb a different amount of energy before denting and cracking the priming pellet.

You only want to go a thou. or two after you feel the primer bottom in the cup; any more than that (assuming the primer is .002" below flush) and you risk damaging the priming pellet....

 

[pods8]

I have been using a full squeeze of the rcbs hand primer, which worked fine with nearly a brick of WLRMs, I am thinking its crushing these 9.5Ms doing it that way.

 

[Lefty7mmstw]

I have been using a full squeeze of the rcbs hand primer, which worked fine with nearly a brick of WLRMs, I am thinking its crushing these 9.5Ms doing it that way.

I'm rather surprised you didn't break the priming tool....

 

[pods8]

There is a spring in the mechanism not really a breakage concern. I had in my head for some reason that limited the pressure to a point it didn't crush them (and that false thought was reinforced by that method working fine with the WLRMs).

In general I am going with some fresh primers of different make for his loads to get a clean slate for him. But I have a gun due any day and a bunch of fire forming to do so I will give the 9.5Ms another shot with lighter seating.

 

[Lefty7mmstw]

There is a spring in the mechanism not really a breakage concern. I had in my head for some reason that limited the pressure to a point it didn't crush them (and that false thought was reinforced by that method working fine with the WLRMs).

In general I am going with some fresh primers of different make for his loads to get a clean slate for him. But I have a gun due any day and a bunch of fire forming to do so I will give the 9.5Ms another shot with lighter seating.

I ram prime by feel and don't fuss with hand priming tools.... I know they had to re-design the Lee tool as some were actually breaking it using too much force.

 

[Canadian Bushman]

I have been using a full squeeze of the rcbs hand primer, which worked fine with nearly a brick of WLRMs, I am thinking its crushing these 9.5Ms doing it that way.

This stood out to me when you stated it earlier in the thread.

When priming with the rcbs tool i apply pressure until i feel the primer come to a stop. On my lapua brass this involves me never completely collapsing the handle.

You may try priming a few with no crush and see if that fixes your problem.

If you are using too much crush you could be bottoming out the anvil inside the cup squeezing the priming mix out of the way of the anvil.

 

[pods8]

I am highly suspicious of that now. I want to get some fresh primers to restart load development for my friend just in case but I have lots of fire forming of my own to do and will retry the 9.5Ms there.